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911nut 911nut is offline
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Join Date: May 2001
Location: Michigan
Posts: 2,511
Originally Posted by 911st View Post
If you vent air from any area after the metering valve to atmosphere the injection system will be supplying fuel for the full amount of the air flowing through it.

You could vent the air but what would happen is there would be extra fuel that might turn the exhaust turbine into a jet engine.
But the point is that when the throttle closes there is very little air flowing through the metering system, only what is flowing through the idle bypass.
The high pressure air is dumped into the engine for emissions. If the throttle is allowed to snap shut there is a small puff of rich exhasut that would foul the cat. Both turbos and n/a cars have schemes to make this tiny amount of exhaust lean for the cat.
My car doesn't have a IA fuel head and doesn't shoot flames so I know I'm not burning any fuel in the turbo.
Paul B.
'91 964 Turbo
Port matched, SC cams, K27/K29 turbo, Roush Performance custom headers w/Tial MV-S dual wastegates, Rarlyl8 muffler, LWFW, GT2 clutch & PP, BL wur, factory RS shifter, RS mounts, FVD timing mod, Big Reds, - 210 lb
Old 12-05-2008, 02:15 PM
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